module Doorkeeper::AccessTokenMixin

def token_generator
  generator_name = Doorkeeper.config.access_token_generator
  generator = generator_name.constantize
  return generator if generator.respond_to?(:generate)
  raise Errors::UnableToGenerateToken, "#{generator} does not respond to `.generate`."
rescue NameError
  raise Errors::TokenGeneratorNotFound, "#{generator_name} not found"
end